Ekaterina M. Zinchenko, Ilana M. Agranovich, Oksana V. Semyachkina-Glushkovskaya
1) Saratov State University, Russia, Astrakhanskaya Str. 83, Saratov 410012, Russia
Ekaterina G. Borisova, Latchezar A. Avramov
2) Institute of Electronics, Bulgarian Academy of Sciences, 72, Tsarigradsko chaussee Blvd., 1784 Sofia, Bulgaria, e-mail: email@example.com
Diffuse reflectance spectroscopy (DRS) could be a very useful tool for detection of different biological pigments, such as melanin, hemoglobin, and bilirubin. Information obtained using such optical technique could be used for an evaluation of tissue healthy state and for qualitative and quantitative analysis.
We used diffuse reflectance spectroscopy technique for detection and comparison of normal and ulcerous stomach mucosa, induced under different types of stress in laboratory animals (rats). The stress types applied on the animals investigated were chemical, social, and alimentary, solely or in combination.
Broad band light illumination in the wavelength region from 400 to 900 nm was applied to obtain reflectance spectra in VIS-NIR spectral range. Fiber optical bundle was used to deliver the illumination and reflected light from the tissue site investigated. All spectra were detected on normal incidence geometry in a distance of 2 mm from the tissue surface. A microspectrometer USB4000 (OceanOptics Inc., Dunedin, USA) was applied to detect the reflectance spectra and to visualize the results. Spectra were stored in ASCII format and compared further to evaluate the differences related to the spectra detected for normal and abnormal tissue sites.
The most significant differences observed were related to the appearance of minima in the DRS signals at the regions of 400-420 nm and 540-575 nm, related to the different forms of oxy and deoxy- hemoglobin. In the case of ulcerous changes observed, deoxyhemoglobin is more pronounced in the spectra detected and the depth of the minimum observed at the region of 560-575 nm could be used as an indicator of the pathological changes. In healthy stomach mucosa the minima in the green spectral region, related to hemoglobin absorption are well pronounced at 543 and 575 nm, which is related to the oxy-hemoglobin form in the blood. Additional decrease of the signal in the far red-near infrared spectral regions was observed for severe forms of ulcerous mucosa, which could be addressed to an increase of the products of hemoglobin dissociation in the ulcers developed. Further investigations are foreseen to develop correlation algorithms between the ulcer stage of development and reflectance spectra of the stomach mucosa detected.
Acknowledgements: This work was supported in part by the Ministry of Education and Science of Russian Federation under Grant № 17.488.2014/K and by National Science Fund of Bulgarian Ministry of Education and Science under grant № DFNI-B02/9/2014.
Dr. Ekaterina Georgieva Borisova
Institute of Electronics, Bulgarian Academy of Sciences, Associate Professor
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